US20230042625A1 - Mechanical seal arrangement having an improved secondary seal - Google Patents
Mechanical seal arrangement having an improved secondary seal Download PDFInfo
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- US20230042625A1 US20230042625A1 US17/793,444 US202017793444A US2023042625A1 US 20230042625 A1 US20230042625 A1 US 20230042625A1 US 202017793444 A US202017793444 A US 202017793444A US 2023042625 A1 US2023042625 A1 US 2023042625A1
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- Prior art keywords
- coating
- secondary seal
- seal
- gap
- mechanical seal
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- 239000011248 coating agent Substances 0.000 claims abstract description 98
- 238000000576 coating method Methods 0.000 claims abstract description 98
- 239000000463 material Substances 0.000 claims abstract description 41
- 238000007789 sealing Methods 0.000 claims abstract description 16
- 239000000126 substance Substances 0.000 claims abstract description 3
- 239000004033 plastic Substances 0.000 claims description 8
- 229920003023 plastic Polymers 0.000 claims description 8
- 239000000945 filler Substances 0.000 claims description 6
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 6
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 6
- -1 polytetrafluoroethylene Polymers 0.000 claims description 5
- 239000004696 Poly ether ether ketone Substances 0.000 claims description 4
- 229920002530 polyetherether ketone Polymers 0.000 claims description 4
- 239000004642 Polyimide Substances 0.000 claims description 3
- 229920006260 polyaryletherketone Polymers 0.000 claims description 3
- 229920001721 polyimide Polymers 0.000 claims description 3
- 229920001971 elastomer Polymers 0.000 claims description 2
- 239000000806 elastomer Substances 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 229920002312 polyamide-imide Polymers 0.000 claims description 2
- 239000004962 Polyamide-imide Substances 0.000 claims 1
- 229920001652 poly(etherketoneketone) Polymers 0.000 claims 1
- 238000001125 extrusion Methods 0.000 description 29
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000007704 transition Effects 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229920008285 Poly(ether ketone) PEK Polymers 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920001643 poly(ether ketone) Polymers 0.000 description 1
- 239000012815 thermoplastic material Substances 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
- F16J15/3436—Pressing means
- F16J15/344—Pressing means the pressing force being applied by means of an elastic ring supporting the slip-ring
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/166—Sealings between relatively-moving surfaces with means to prevent the extrusion of the packing
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
- F16J15/3436—Pressing means
- F16J15/3452—Pressing means the pressing force resulting from the action of a spring
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
- F16J15/38—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member sealed by a packing
Definitions
- the present invention relates to a mechanical seal arrangement having an improved secondary seal.
- Secondary seals in various designs which include secondary seals are known from prior art. Such secondary seals, for example, sealing on a back side of a slide ring suffer from the fact that the secondary seals are exposed to high pressures and/or high temperatures. Moreover, secondary seals are required to be minimally axially movable so as to be able to compensate for axial displacements, for example of a shaft or the like which is to be sealed, or for movements occurring when starting up and braking a machine. In addition, the secondary seal is to perform a sealing function when the machine is at a standstill.
- the secondary seal Due to the pressure differences between the medium to be sealed and the atmosphere, which can be in the range of several 105 Pa, the secondary seal is at risk to be partially drawn into a gap on the slide ring where it is supposed to seal, so that a so-called extrusion plume may be formed on the sliding ring, i.e. material from the secondary seal is drawn into the gap.
- This extrusion plume in the gap on the slide ring can cause malfunctions during operation, even resulting in possible total failure of the secondary seal. However, this must absolutely be avoided.
- a mechanical seal arrangement comprising a secondary seal, which provides an additional ring element made of a material which is different at the gap is known, for example, from DE10 2012 022 465 A1. Although this basically may reduce the occurrence of secondary seal extrusion into in the gap, it is required to provide a ring for the secondary seal which is specifically designed depending on application.
- the mechanical seal arrangement according to the invention having the features of claim 1 has the advantage that the secondary seal comprises a coating thereby reducing any extrusion tendency of the secondary seal in a gap against which the secondary seal seals.
- this will be achieved by providing the secondary seal having a coating which is bonded to a base material of the secondary seal via substance-to-substance bonding.
- the coating is provided on two sides of the secondary seal, i. e. on a first side facing toward one of the sliding rings and on a second side facing toward a sleeve-shaped component on which the gap to the slide ring is present with a predetermined gap height.
- a stiffness of the coating of the secondary seal is greater than a stiffness of the base material.
- a maximum thickness of the coating is less than or equal to the gap height of the gap, especially less than or equal to half of the gap height. If any material of the secondary seal now extrudes into the seal gap when operating the mechanical seal, regions of the first and second sides, especially where the coating is present, will be extruded into the gap due to the coating of the secondary seal. This will result in overlapping of the coated side regions of the secondary seal in the gap, as material from both the first side and the second side, each having the coating, extrudes into the gap.
- the first and second sides of the secondary seal having the coating formed thereon are adjacent to each other, such that a transition zone between the first and second sides of the secondary seal especially will be provided with the coating.
- the solution according to the invention appears to be surprisingly simple even to a person skilled in the art, since providing a stiffness to the coating higher than that of base material of the secondary seal, some small extrusion into the gap is allowed, but this will be subsequently be stopped by proficiently selecting the coating, and further extrusion will be prevented.
- the thickness of the coating is exactly half of the gap height. This still allows the coating to be applied to the secondary seal at a very low cost and, if during operation any situation occurs extruding the secondary seal into the gap, material from the secondary seal will then be extruded into the gap which is exclusively from the coating, due to the thickness of the coating corresponding to half of the gap height.
- one half of the gap is filled with the coating on the first side of the secondary seal and the other half of the gap is filled with the coating on the second side of the secondary seal.
- a thickness of the coating is at least as thick as a 1/10 of the gap height, more preferably at least a 1 ⁇ 5 of the gap height, even more preferably 1 ⁇ 4 of the gap height.
- the coating preferably has a thickness in a range from 20 ⁇ m to 50 ⁇ m.
- the coating is provided only partially on the first side and/or on the second side of the secondary seal.
- the secondary seal is in contact with the surfaces of the mechanical seal to be sealed both with the coating and with an uncoated area of base material.
- the uncoated regions are made of the base material of the secondary seal, thus enabling reliable sealing at their contact surfaces.
- sealing action is performed by the uncoated regions of the secondary seal and the coating can be designed so as extrusion into the gap will be minimized.
- a size of the coating surface on the secondary seal on the first and second sides is preferably the same.
- a width C of the coating, starting from the inner edge of the secondary seal, on the first and second sides of the secondary seal is in a range of four to ten times the gap height of the gap, especially five to six times the gap height.
- first and second sides of the secondary seal are provided completely covered with a coating. This has advantages, especially in terms of producing the coating at minimum cost, since the entire first and second sides of the secondary seal may then be coated in a simple manner. If the coating is applied only partially, it is required to work using a mask or to mask off areas on the secondary seal, which will slightly increase the manufacturing effort.
- a value of a stiffness of the coating in a range of two to twelve times a stiffness of the base material of the secondary seal is particularly preferred.
- the stiffness of the coating is at least five times the stiffness of the base material.
- the coating preferably includes plastic material, especially a thermoplastic material and further preferably a single-grade plastic or a plastic material including filler material.
- the filler material is preferably carbon graphite.
- polyetherketone (PEK) can be used as the plastic material, especially polyaryletherketone (PAEK) or polyetheretherketone (PEEK) or polyamideimide (PAI) or polyimide (PI) or any mixture thereof.
- the plastic materials may also contain small amounts of fillers, e.g. carbon or PTFG.
- the base material of the secondary seal is preferably polytetrafluoroethylene (PTFE) or an elastomer or polytetrafluoroethylene with filler, especially with carbon graphite.
- PTFE polytetrafluoroethylene
- elastomer or polytetrafluoroethylene with filler, especially with carbon graphite.
- the secondary seal seals directly against a sealing surface of the mechanical seal, especially against the stationary sealing surface. Further preferably, the secondary seal seals directly against the sleeve-shaped component. Alternatively, an intermediate component is provided between the slide ring and the sleeve-shaped component.
- the secondary seal seals against a pressure side of the mechanical seal, so that the secondary seal is exposed to the pressure to be sealed.
- FIG. 1 is a schematic view of a mechanical seal arrangement according to a first embodiment of the invention with a secondary seal being in a non-extruded state
- FIG. 2 is an enlarged schematic view of the secondary seal of FIG. 1 ,
- FIG. 3 is a schematic view of the mechanical seal arrangement of FIG. 1 with a secondary seal being in an extruded state
- FIG. 4 is a diagram showing the extrusion E of the secondary seal of FIGS. 2 and 3 as a function of a pressure P for different layer thicknesses in comparison with an uncoated secondary seal, and
- FIG. 5 is a schematic representation of a mechanical seal arrangement having a secondary seal according to a second embodiment of the invention.
- the mechanical seal arrangement 1 comprises a mechanical seal 2 having a rotating slide ring 21 and a stationary slide ring 22 defining a sealing gap 23 therebetween.
- the mechanical seal 2 seals off a product region 11 from an atmospheric region 12 .
- the product region 11 is under high pressure.
- the sealing action is performed at a shaft 8 , the rotating slide ring 21 being connected to the shaft 8 .
- the mechanical seal 2 further comprises a biasing element 6 , which, in this embodiment, biases the stationary slide ring 22 against the rotating slide ring 21 .
- Reference number 9 denotes a stationary housing of the mechanical seal arrangement.
- a sleeve-shaped component 4 which is stationary and through which the shaft 8 is passed.
- the sleeve-shaped component 4 is arranged partly radially inside a secondary seal 3 and radially inside the stationary mechanical slide ring 22 . This results in a gap 5 between the sleeve-shaped component 4 and the stationary slide ring 22 .
- the mechanical seal arrangement 1 is designed such that the product region 11 also extends to a back side 22 a of the stationary slide ring 22 .
- the secondary seal 3 is also exposed to the pressure in the product region 11 , which is indicated by the arrows P in FIG. 1 .
- the secondary seal 3 has a coating 7 , which may be seen in detail in FIG. 2 .
- the coating 7 is formed on a first side 31 of the secondary seal as a first coating region 71 and on a second side 32 of the secondary seal as a second coating region 72 .
- the first side 31 and the second side 32 are not completely coated, but an uncoated area 33 is still provided on the first side and an uncoated area 34 is provided on the second side.
- the coating 7 is thereby formed at a transition zone 25 between the first side 31 and the second side 32 .
- the transition zone 25 is an edge of the secondary seal 3 (cf. FIG. 2 ).
- a width C of the coating is the same on the first side 31 and the second side 32 .
- FIG. 2 shows the secondary seal 3 being in the non-extruded state, in which the secondary seal 3 is not extruded into the gap 5 .
- FIG. 3 shows the extruded state, which may occur during operation, especially due to the high pressure difference between the product region 11 and the atmosphere region 12 .
- the secondary seal 3 is extruded into the gap 5 .
- a thickness D of the coating corresponds to half of the gap height H of the gap 5 , only coating regions 71 , 72 from the first side 31 and the second side 32 of the secondary seal 3 are thus extruded into the gap 5 (cf. FIG. 3 ).
- a stiffness of the coating 7 is greater than a stiffness of the base material of the secondary seal 3 .
- the coating is preferably a polyetherketone, especially PEEK, and the base material of the secondary seal is polytetrafluoroethylene.
- the base material of the secondary seal 3 is thus in direct contact with the back side 22 a of the stationary slide ring 22 at the uncoated region 33 and with the sleeve-shaped component 4 at the uncoated region 34 .
- secure sealing may be achieved in those regions 33 , 34 , so that the sealing properties of the secondary seal 3 are not significantly affected by the coating 7 .
- FIG. 4 shows a diagram of a comparison of an extrusion E (dimensionless) of various secondary seals into the gap 5 above the pressure P in Pa in the product region 11 at ambient temperature (20° C.).
- the curve identified by the reference number 13 is a secondary seal without coating.
- a coating 7 having a thickness D of 25 ⁇ m is provided in the curve identified by the reference number 14 .
- a coating of 50 ⁇ m is provided in the curve identified by the reference number 15 .
- a gap height H is 100 ⁇ m in all tests and a stiffness of the coating is greater than that of the base material by a factor of 5 in each case.
- the extrusion E is approximately the same for all curves 13 , 14 , 15 .
- the extrusion tendency of the secondary seal without coating becomes significantly higher.
- the difference between the length of the extrusion plumes at a pressure of 400 ⁇ 10 5 Pa between the coating of 25 ⁇ m and the coating of 50 ⁇ m is only in the range of about 10 ⁇ m. It thus may be concluded that a coating thicker than 50 ⁇ m would not create extrusion plumes into gap 5 which are significantly different.
- FIG. 5 shows a mechanical seal arrangement 1 according to a second embodiment of the invention, wherein equal or functionally equal parts are identified using the same reference numbers.
- the coating 7 is provided such that both the first side 31 and the second side 32 of the secondary seal are completely covered with the coating 7 .
- this allows to provide a coating that is very easy to apply, since no regions on the secondary seal 3 are required to be covered or taped to prevent a coating 7 to be coated onto all regions of the first and second sides.
- a thickness D of the coating 7 is selected such that the thickness D corresponds to half of the gap height H. Otherwise, this example embodiment corresponds to the previous embodiment example, so that reference can be made to the description given therein.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Sealing Devices (AREA)
Abstract
Description
- The present invention relates to a mechanical seal arrangement having an improved secondary seal.
- Mechanical seals in various designs which include secondary seals are known from prior art. Such secondary seals, for example, sealing on a back side of a slide ring suffer from the fact that the secondary seals are exposed to high pressures and/or high temperatures. Moreover, secondary seals are required to be minimally axially movable so as to be able to compensate for axial displacements, for example of a shaft or the like which is to be sealed, or for movements occurring when starting up and braking a machine. In addition, the secondary seal is to perform a sealing function when the machine is at a standstill. Due to the pressure differences between the medium to be sealed and the atmosphere, which can be in the range of several 105 Pa, the secondary seal is at risk to be partially drawn into a gap on the slide ring where it is supposed to seal, so that a so-called extrusion plume may be formed on the sliding ring, i.e. material from the secondary seal is drawn into the gap. This extrusion plume in the gap on the slide ring can cause malfunctions during operation, even resulting in possible total failure of the secondary seal. However, this must absolutely be avoided.
- To avoid such extrusions of secondary seals, a mechanical seal arrangement comprising a secondary seal, which provides an additional ring element made of a material which is different at the gap is known, for example, from DE10 2012 022 465 A1. Although this basically may reduce the occurrence of secondary seal extrusion into in the gap, it is required to provide a ring for the secondary seal which is specifically designed depending on application.
- It is therefore the object of the present invention to provide a mechanical seal arrangement which, while having simple design and simple low-cost manufacturability, comprises an improved secondary seal which especially also provides reliable sealing actions when sealing media which are exposed to very high pressure. This object will be solved by providing a mechanical seal arrangement having the features of
claim 1. The subclaims will set forth preferred further embodiments of the invention. - Contrary to the foregoing, the mechanical seal arrangement according to the invention having the features of
claim 1 has the advantage that the secondary seal comprises a coating thereby reducing any extrusion tendency of the secondary seal in a gap against which the secondary seal seals. According to the invention, this will be achieved by providing the secondary seal having a coating which is bonded to a base material of the secondary seal via substance-to-substance bonding. The coating is provided on two sides of the secondary seal, i. e. on a first side facing toward one of the sliding rings and on a second side facing toward a sleeve-shaped component on which the gap to the slide ring is present with a predetermined gap height. Herein, a stiffness of the coating of the secondary seal is greater than a stiffness of the base material. Furthermore, a maximum thickness of the coating is less than or equal to the gap height of the gap, especially less than or equal to half of the gap height. If any material of the secondary seal now extrudes into the seal gap when operating the mechanical seal, regions of the first and second sides, especially where the coating is present, will be extruded into the gap due to the coating of the secondary seal. This will result in overlapping of the coated side regions of the secondary seal in the gap, as material from both the first side and the second side, each having the coating, extrudes into the gap. The first and second sides of the secondary seal having the coating formed thereon are adjacent to each other, such that a transition zone between the first and second sides of the secondary seal especially will be provided with the coating. However, as a stiffness of the coating is greater than a stiffness of the base material of the secondary seal, large tensile and/or shear stresses result in the region of the coating which has not yet been extruded into the gap, so that further extrusion of the secondary seal into the gap will be prevented. Thus, proficient arrangement of the stiffer coating on the secondary seal can prevent material from the secondary seal from extruding too deeply into the gap. In this regard, the solution according to the invention appears to be surprisingly simple even to a person skilled in the art, since providing a stiffness to the coating higher than that of base material of the secondary seal, some small extrusion into the gap is allowed, but this will be subsequently be stopped by proficiently selecting the coating, and further extrusion will be prevented. - Preferably, the thickness of the coating is exactly half of the gap height. This still allows the coating to be applied to the secondary seal at a very low cost and, if during operation any situation occurs extruding the secondary seal into the gap, material from the secondary seal will then be extruded into the gap which is exclusively from the coating, due to the thickness of the coating corresponding to half of the gap height. Thus, one half of the gap is filled with the coating on the first side of the secondary seal and the other half of the gap is filled with the coating on the second side of the secondary seal.
- Further preferably, a thickness of the coating is at least as thick as a 1/10 of the gap height, more preferably at least a ⅕ of the gap height, even more preferably ¼ of the gap height. The coating preferably has a thickness in a range from 20 μm to 50 μm.
- In particular, good durability and high sealing performance will be achieved if the coating is provided only partially on the first side and/or on the second side of the secondary seal. In other words, the secondary seal is in contact with the surfaces of the mechanical seal to be sealed both with the coating and with an uncoated area of base material. The uncoated regions are made of the base material of the secondary seal, thus enabling reliable sealing at their contact surfaces. Thus, sealing action is performed by the uncoated regions of the secondary seal and the coating can be designed so as extrusion into the gap will be minimized.
- A size of the coating surface on the secondary seal on the first and second sides is preferably the same. Particularly preferably, a width C of the coating, starting from the inner edge of the secondary seal, on the first and second sides of the secondary seal is in a range of four to ten times the gap height of the gap, especially five to six times the gap height.
- Alternatively, the first and second sides of the secondary seal are provided completely covered with a coating. This has advantages, especially in terms of producing the coating at minimum cost, since the entire first and second sides of the secondary seal may then be coated in a simple manner. If the coating is applied only partially, it is required to work using a mask or to mask off areas on the secondary seal, which will slightly increase the manufacturing effort.
- A value of a stiffness of the coating in a range of two to twelve times a stiffness of the base material of the secondary seal is particularly preferred. Especially, the stiffness of the coating is at least five times the stiffness of the base material.
- The coating preferably includes plastic material, especially a thermoplastic material and further preferably a single-grade plastic or a plastic material including filler material. The filler material is preferably carbon graphite. For example, polyetherketone (PEK) can be used as the plastic material, especially polyaryletherketone (PAEK) or polyetheretherketone (PEEK) or polyamideimide (PAI) or polyimide (PI) or any mixture thereof. The plastic materials may also contain small amounts of fillers, e.g. carbon or PTFG.
- The base material of the secondary seal is preferably polytetrafluoroethylene (PTFE) or an elastomer or polytetrafluoroethylene with filler, especially with carbon graphite.
- Preferably, the secondary seal seals directly against a sealing surface of the mechanical seal, especially against the stationary sealing surface. Further preferably, the secondary seal seals directly against the sleeve-shaped component. Alternatively, an intermediate component is provided between the slide ring and the sleeve-shaped component.
- Particularly preferably, the secondary seal seals against a pressure side of the mechanical seal, so that the secondary seal is exposed to the pressure to be sealed.
- Preferred embodiments of the invention will be described in detail below while reference will be made to the accompanying drawing, wherein:
-
FIG. 1 is a schematic view of a mechanical seal arrangement according to a first embodiment of the invention with a secondary seal being in a non-extruded state, -
FIG. 2 is an enlarged schematic view of the secondary seal ofFIG. 1 , -
FIG. 3 is a schematic view of the mechanical seal arrangement ofFIG. 1 with a secondary seal being in an extruded state, -
FIG. 4 is a diagram showing the extrusion E of the secondary seal ofFIGS. 2 and 3 as a function of a pressure P for different layer thicknesses in comparison with an uncoated secondary seal, and -
FIG. 5 is a schematic representation of a mechanical seal arrangement having a secondary seal according to a second embodiment of the invention. - In the following, a
mechanical seal arrangement 1 according to a first preferred embodiment of the invention will be described in detail while making reference to theFIGS. 1 to 4 . - As may be seen from
FIG. 1 , themechanical seal arrangement 1 comprises amechanical seal 2 having a rotatingslide ring 21 and astationary slide ring 22 defining asealing gap 23 therebetween. - The
mechanical seal 2 seals off aproduct region 11 from anatmospheric region 12. Theproduct region 11 is under high pressure. - The sealing action is performed at a
shaft 8, the rotatingslide ring 21 being connected to theshaft 8. - The
mechanical seal 2 further comprises abiasing element 6, which, in this embodiment, biases thestationary slide ring 22 against the rotatingslide ring 21.Reference number 9 denotes a stationary housing of the mechanical seal arrangement. - Furthermore, a sleeve-
shaped component 4 is provided which is stationary and through which theshaft 8 is passed. Herein, the sleeve-shaped component 4 is arranged partly radially inside asecondary seal 3 and radially inside the stationarymechanical slide ring 22. This results in agap 5 between the sleeve-shaped component 4 and thestationary slide ring 22. - As may be seen from
FIG. 1 , themechanical seal arrangement 1 is designed such that theproduct region 11 also extends to aback side 22 a of thestationary slide ring 22. As a result, thesecondary seal 3 is also exposed to the pressure in theproduct region 11, which is indicated by the arrows P inFIG. 1 . - The
secondary seal 3 has acoating 7, which may be seen in detail inFIG. 2 . Thecoating 7 is formed on afirst side 31 of the secondary seal as afirst coating region 71 and on asecond side 32 of the secondary seal as asecond coating region 72. In this case, thefirst side 31 and thesecond side 32 are not completely coated, but anuncoated area 33 is still provided on the first side and anuncoated area 34 is provided on the second side. Thecoating 7 is thereby formed at atransition zone 25 between thefirst side 31 and thesecond side 32. In this embodiment, thetransition zone 25 is an edge of the secondary seal 3 (cf.FIG. 2 ). Herein, a width C of the coating is the same on thefirst side 31 and thesecond side 32. - A thickness D of the coating is constant on both the first and second sides.
FIG. 2 shows thesecondary seal 3 being in the non-extruded state, in which thesecondary seal 3 is not extruded into thegap 5.FIG. 3 , on the other hand, shows the extruded state, which may occur during operation, especially due to the high pressure difference between theproduct region 11 and theatmosphere region 12. - As may be seen from
FIG. 3 , thesecondary seal 3 is extruded into thegap 5. However, this results in only a veryshort extrusion plume 16 in the axial direction X-X of the mechanical seal arrangement, since, as it is shown inFIG. 3 , only coated areas of thesecondary seal 3 will be extruded into the gap 5 (arrow A). - Since in this embodiment example a thickness D of the coating corresponds to half of the gap height H of the
gap 5, only coatingregions first side 31 and thesecond side 32 of thesecondary seal 3 are thus extruded into the gap 5 (cf.FIG. 3 ). - A stiffness of the
coating 7 is greater than a stiffness of the base material of thesecondary seal 3. The coating is preferably a polyetherketone, especially PEEK, and the base material of the secondary seal is polytetrafluoroethylene. - Due to the higher stiffness of the
coating 7 compared to the base material of thesecondary seal 3, limitation of a length L of theextrusion plume 16 results in tensile and/or shear stresses in thestiffer coating 7 occurring both on thefirst side 31 and thesecond side 32, thus counteracting any further extrusion of thesecondary seal 3 into thegap 5. The tensile and/or shear stresses are indicated by the double arrow B inFIG. 3 . These tensile stresses B in thecoating areas secondary seal 3 from being extruded further into thegap 5. - Since the
coating 7 is not provided entirely on thefirst side 31 and thesecond side 32 of thesecondary seal 3, the base material of thesecondary seal 3 is thus in direct contact with theback side 22 a of thestationary slide ring 22 at theuncoated region 33 and with the sleeve-shapedcomponent 4 at theuncoated region 34. As a result, secure sealing may be achieved in thoseregions secondary seal 3 are not significantly affected by thecoating 7. -
FIG. 4 shows a diagram of a comparison of an extrusion E (dimensionless) of various secondary seals into thegap 5 above the pressure P in Pa in theproduct region 11 at ambient temperature (20° C.). Herein, the curve identified by thereference number 13 is a secondary seal without coating. In the curve identified by thereference number 14, acoating 7 having a thickness D of 25 μm is provided. In the curve identified by thereference number 15, a coating of 50 μm is provided. A gap height H is 100 μm in all tests and a stiffness of the coating is greater than that of the base material by a factor of 5 in each case. - As may be seen from the diagram of
FIG. 4 , up to a range of about 200×105 Pa, the extrusion E is approximately the same for allcurves extrusion plume 16 results in the range of E=1 approximately. In contrast, forcurve 14 showing a coating having a thickness of 25 μm, the extrusion plume in the range of 400×105 Pa is significantly smaller by a factor of five, with E=0.2 appx. Further reduction of the extrusion plume to E=0.15 appx. may be achieved using a coating thickness of 50 μm for thecoating 7. - However, as may be seen from the diagram of
FIG. 4 , the difference between the length of the extrusion plumes at a pressure of 400×105 Pa between the coating of 25 μm and the coating of 50 μm is only in the range of about 10 μm. It thus may be concluded that a coating thicker than 50 μm would not create extrusion plumes intogap 5 which are significantly different. - The best results in extrusion preventing will be achieved when the layer thickness D is half of the gap height H of the
gap 5. As it is shown inFIG. 3 , an extrusion performance will then be obtained wherein only a verysmall extrusion plume 16 is drawn into thegap 5 and the tensile and/or shear stresses B in thecoating 7 will subsequently prevent any further extrusion. -
FIG. 5 shows amechanical seal arrangement 1 according to a second embodiment of the invention, wherein equal or functionally equal parts are identified using the same reference numbers. - In contrast to the first example embodiment, in the second example embodiment, the
coating 7 is provided such that both thefirst side 31 and thesecond side 32 of the secondary seal are completely covered with thecoating 7. In particular, this allows to provide a coating that is very easy to apply, since no regions on thesecondary seal 3 are required to be covered or taped to prevent acoating 7 to be coated onto all regions of the first and second sides. In turn, a thickness D of thecoating 7 is selected such that the thickness D corresponds to half of the gap height H. Otherwise, this example embodiment corresponds to the previous embodiment example, so that reference can be made to the description given therein. -
- 1 Mechanical seal arrangement
- 2 Mechanical seal
- 3 Secondary seal
- 4 Sleeve-type component
- 5 Gap
- 6 Biasing member
- 7 Coating
- 8 Shaft
- 9 Housing
- 11 Product region
- 12 Atmosphere region
- 13 Secondary seal without coating (prior art)
- 14 Secondary seal with coating of 25 μm
- 15 Secondary seal with coating of 50 μm
- 16 Extrusion plume
- 21 Rotating slide ring
- 22 Stationary slide ring
- 22 a back side of the stationary slide ring
- 23 Sealing gap
- 25 Transition zone
- 31 First side of the secondary seal
- 32 Second side of the secondary seal
- 33 Uncoated region on the first side of the secondary seal
- 34 Uncoated region on the second side of the secondary seal
- 71 Coating region on the first side
- 72 Coating region on the second side
- A Extrusion direction
- B Tensile stress in the coating
- C Width
- D Thickness of the coating
- E Extrusion
- H Gap height
- L Length of the extrusion plume
- P Pressure exerted on secondary seal
- X-X Axial direction
Claims (12)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102020200914.7A DE102020200914B4 (en) | 2020-01-27 | 2020-01-27 | Mechanical seal arrangement with improved secondary seal |
DE102020200914.7 | 2020-01-27 | ||
PCT/EP2020/083145 WO2021151539A1 (en) | 2020-01-27 | 2020-11-24 | Mechanical seal arrangement having an improved secondary seal |
Publications (2)
Publication Number | Publication Date |
---|---|
US20230042625A1 true US20230042625A1 (en) | 2023-02-09 |
US11892082B2 US11892082B2 (en) | 2024-02-06 |
Family
ID=73598076
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/793,444 Active 2041-01-10 US11892082B2 (en) | 2020-01-27 | 2020-11-24 | Mechanical seal arrangement having an improved secondary seal |
Country Status (4)
Country | Link |
---|---|
US (1) | US11892082B2 (en) |
EP (1) | EP4097379A1 (en) |
DE (1) | DE102020200914B4 (en) |
WO (1) | WO2021151539A1 (en) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009030298A1 (en) * | 2007-08-29 | 2009-03-12 | Burgmann Industries Gmbh & Co. Kg | Seal element, in particular secondary seal element of a slide ring seal |
WO2010020364A1 (en) * | 2008-08-19 | 2010-02-25 | Burgmann Industries Gmbh & Co. Kg | Slide ring seal arrangement having an improved secondary seal |
US20180238452A1 (en) * | 2017-02-23 | 2018-08-23 | Aes Engineering Ltd. | Mechanical seal |
DE102017214132A1 (en) * | 2017-08-14 | 2019-02-14 | Eagleburgmann Germany Gmbh & Co. Kg | Mechanical seal assembly and mechanical seal kit |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2264986B (en) | 1992-03-07 | 1996-02-28 | Dowty Seals Ltd | Ring seal |
DE4409021A1 (en) | 1994-03-16 | 1995-09-21 | Burgmann Dichtungswerk Feodor | Non-contact, gas-lubricated mechanical seal |
US5799953A (en) | 1995-05-25 | 1998-09-01 | American Variseal | Capped spring-energized seal |
DE202007017783U1 (en) | 2007-12-18 | 2008-03-06 | Burgmann Industries Gmbh & Co. Kg | The mechanical seal assembly |
DE102012022465B4 (en) | 2012-11-15 | 2014-09-25 | Eagleburgmann Germany Gmbh & Co. Kg | Mechanical seal assembly with improved secondary seal |
DE102015110944A1 (en) | 2015-07-07 | 2017-01-12 | W.L. Gore & Associates Gmbh | ring seal |
JP6653678B2 (en) | 2017-03-31 | 2020-02-26 | 株式会社リケン | Seal member |
FR3068101B1 (en) | 2017-06-27 | 2020-06-19 | Centre Technique Des Industries Mecaniques | MULTI-LAYER SEAL |
-
2020
- 2020-01-27 DE DE102020200914.7A patent/DE102020200914B4/en active Active
- 2020-11-24 US US17/793,444 patent/US11892082B2/en active Active
- 2020-11-24 WO PCT/EP2020/083145 patent/WO2021151539A1/en unknown
- 2020-11-24 EP EP20812261.4A patent/EP4097379A1/en active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009030298A1 (en) * | 2007-08-29 | 2009-03-12 | Burgmann Industries Gmbh & Co. Kg | Seal element, in particular secondary seal element of a slide ring seal |
WO2010020364A1 (en) * | 2008-08-19 | 2010-02-25 | Burgmann Industries Gmbh & Co. Kg | Slide ring seal arrangement having an improved secondary seal |
US20180238452A1 (en) * | 2017-02-23 | 2018-08-23 | Aes Engineering Ltd. | Mechanical seal |
DE102017214132A1 (en) * | 2017-08-14 | 2019-02-14 | Eagleburgmann Germany Gmbh & Co. Kg | Mechanical seal assembly and mechanical seal kit |
Also Published As
Publication number | Publication date |
---|---|
DE102020200914A1 (en) | 2021-07-29 |
DE102020200914B4 (en) | 2021-08-12 |
WO2021151539A1 (en) | 2021-08-05 |
EP4097379A1 (en) | 2022-12-07 |
US11892082B2 (en) | 2024-02-06 |
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